CASPER, Wyo.  Calm, cooler weather and unusually high humidity Friday helped firefighters battling a wildfire that had threatened hundreds of homes and burned four cabins.

State Forester Bill Crapser said people were allowed to return to 60 homes, while around 300 remained evacuated.

Officials reduced their estimates of the fire's reach to 11,700 acres _ about 18 square miles _ and said containment lines had been established around about 70 percent of the fire.

"We're starting to mop up in some areas,"said Vince Mazzier, spokesman for the National Incident Management Team."The weather really helped us out."

Humidity was up from 10 percent earlier in the week to 50 percent Friday, and the air had stilled following gusts up to 50 mph a day earlier.

Lighting sparked the fire Monday and it quickly spread over Casper Mountain, prompting the evacuations Tuesday and Wednesday. Four cabins burned.

In Utah, a firefighter died Thursday while battling a 250-acre fire about 130 miles south of Salt Lake City. Spencer Koyle, 33, a 15-year veteran of fighting wildfires, died after being trapped in the blaze as winds suddenly shifted.

It was the first death this year of a federal firefighter while battling a blaze, according to the National Interagency Fire Center.

Authorities had mostly contained a wildfire that sent clouds of thick smoke over southern Oklahoma and forced the closure of main highways through the Arbuckle Mountains area, authorities said Friday.

Authorities had closed 15-mile sections of each highway as the fire burned across an estimated 2,500 acres, threatening homes of about 30 residents.

Nevada firefighters gained ground on one of five big blazes that combined have scorched more than 100 square miles of rangeland and wildlife habitat. Ranchers were helping Thursday to round up thousands of cattle and sheep to move them to safety.

The largest of the range fires was 80 percent contained Thursday at 67 square miles. Officials hoped to have it fully surrounded with fire line by nightfall Friday.